The objective of the proposed research is to use cellular genetic methodologies, particularly chromosome and gene transfer techniques, to construct a series of hybrid clones each containing a different single human chromosome. The ultimate goal is to establish a complete set of hybrids each containing one of the 24 different human chromosomes. Two approaches will be used to achieve this goal: (1) Use of microcells containing small numbers of human chromosomes for fusion with recipient auxotrophic mutant cells to establish hybrids containing single human chromosomes; and (2) use of a selective marker introduced randomly but stably into different human chromosomes by gene transfer techniques, and followed by microcell-mediated chromosome transfer to establish hybrids retaining single human chromosomes. In addition, cell hybrids containing single, partial human chromosomes with specific terminal deletions will also be established using similar approaches. Three gene transfer techniques will be compared in these experiments for developing a most effective method to achieve gene transfer with high frequency and with maximally random and stable association with the recipient genome. These hybrids will be useful not only for chromosomal, regional and fine structure mapping of many human genes, but also for studying molecular and cellular mechanisms underlying expression and regulation of the human genome. Better understanding of the genome structure, function and regulation in man and other mammals is essential for elucidating mechanisms underlying inherited and developmental human diseases including cancer.